.box {
  background-color: #f4f0e5;
  width: 400px;
  height: 300px;
  display: flex;
}
.box .item {
  width: 100px;
  height: 50px;
  background-color: #d9d9f4;
  color: #fff;
  flex-grow: 0;
}
.box .item:nth-of-type(1) {
  flex-grow: 2;
}
.box .item:nth-of-type(2) {
  background-color: #ceeee5;
  flex-grow: 1;
}
.box .item:nth-of-type(3) {
  background-color: #9cd3a9;
  flex-grow: 1;
}
